This invention relates to optical sensing devices for reading bar codes and other data codes, and particularly such devices of the portable type having a memory for storing codes read by the device for subsequent entry in a host computer.
Optical code readers are used in a wide variety of applications involving tabulation and identification, such as supermarket checkouts, inventory control, security, etc. Some of these code readers are self-contained and portable, having their own battery power source, memory and clock, and having an accompanying multipurpose battery charger which also acts as the reader's output interface with a host computer, as shown, for example, in U.S. Pat. No. 4,471,218. The output is accomplished by coded pulsing of the light source of the device, which is sensed by a light sensor in the charger receptacle. The code reader is also capable of receiving commands through its optical sensor. A somewhat similar portable code reader has been marketed by Hand Held Products Inc. under the trademark Micro-Wand.
Typical optical code readers of the portable type are of an elongate configuration of a relatively large diameter, such as the Micro-Wand reader or that shown in the above-mentioned U.S. Pat. No. 4,471,218. Similar portable configurations are shown in U.S. Pat. Nos. 3,826,900, 4,091,270 and 4,179,064. Such devices are inconvenient to carry in a pocket and are too bulky to be carried in a wallet or checkbook, as can a pocket calculator or a credit card. The inconveniently large diametric thickness of such devices is largely dictated by the space requirements of their optical reader heads which are normally of the focusing type as shown, for example, in U.S. Pat. Nos. 3,417,234, 3,868,514, 4,143,809 and 4,443,694. Although the thinnest types of optical reader heads are of the contact type whereby a fiber optic filament connected to a light sensor may be placed in direct contact with a data code, as shown, for example, in U.S. Pat. No. 4,434,360, the beneficial effect which such a head construction can have on the miniaturization and portability of the overall reader device has apparently not previously been recognized.
The outputs from the memories of such devices have not previously been obtainable in a particularly efficient or reliable manner, despite the aforementioned provision of output interfaces in the battery chargers for the devices. One drawback is that no means is available for placing a group of individual code readers simultaneously into a single charger which then will receive their respective outputs automatically and transmit them to a host computer without the need for personal supervision of the process. Another problem is that, although commands can be given to the code reader optically in the receptacle as suggested by the aforementioned U.S. Pat. No. 4,471,218, the need for exact alignment of the code reader with the receptacle's light source to receive commands optically can create a reliability problem, and make it impossible for the reader to receive and transmit simultaneously. AccordingIy, the inability of the reader to receive commands reliably while in the receptacle, or to sense whether or not it is properly positioned in a receptacle, contributes further to the need for supervision and also to the likelihood of malfunction of the output process.